THIS AVALANCHE ADVISORY EXPIRED ON February 18, 2017 @ 7:02 am
Avalanche Advisory published on February 17, 2017 @ 7:02 am
Issued by Dave Bingaman - Payette Avalanche Center
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The Avalanche Danger is CONSIDERABLE today above 7000 feet on wind affected slopes. Winds in excess of 35 MPH were recorded in the upper elevations yesterday which quickly created a new batch of wind slabs.  These new slabs and the new snow fell on a variety of  slick, old snow surfaces which will create poor bonding in many places. Below 6000 feet there is a possibility of wet loose avalanches due to yesterday's rain and above freezing temperatures.  

How to read the advisory


  • Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wind Slab
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Yesterday's storm came in windy and wet.  S and SW winds were clocked on Granite Mountain yesterday afternoon at 36 mph while Tamarack Resort clocked gusts over 55mph(watch video).  Wind slabs were forming rapidly on all leeward terrain yesterday throughout the day.  On the ridgetops, cornices and wind spines/drifts were also rapidly growing. These new wind features have all been deposited on a highly variable old snow surface. Wednesday we found very firm rain and sun crusts on all but the most protected, high elevation slopes. The new wind slabs were showing signs of instability yesterday as they produced shooting cracks under the weight of a skier near the ridgetops.  Not much new snow accompanied the winds yesterday because of above freezing temperatures but what did accumulate yesterday was struggling to stick to the firm surface below.  Pay attention to the visual clues of wind affected snow today and avoid steep, upper elevation wind loaded terrain. Cornices are VERY large and sensitive right now, avoid travel on heavily corniced ridgelines.  Use rocks and vegetation as a reference to where overhanging snow begins and terra firma ends. If you are beyond the last row of ridgetop trees, you are probably on a cornice.  Additionally, tomorrow's storm will likely add quite a bit of new snow to the game as well so watch for the growth of poorly bonded storm slabs at all elevations as we get additional snow over the next few days.

Here is the 24 hour wind graph from Granite Mountain Wx station. 

 

Avalanche Problem 2: Loose Wet
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Lower elevation temperatures were still above freezing this morning at 5am. Snotel sites between 6200 and 6500 feet recorded temperatures falling below freezing between 1 pm and 11 pm yesterday.  In addition, rain crept up to just right around the 6500 foot level yesterday in the mountains.  Today, you can expect soggy conditions again in the lower elevations with firm snow with a dusting of new snow on top of it in the middle elevations.  The high elevations picked up 2-5 inches of new snow showing the variability of conditions based on above average temperatures.  The possibility of wet, loose avalanches on steep, lower elevation terrain will stick around for the next few days as day time high temperatures exceed 35 degrees and lows hover near the freezing mark. Precipitation in the valleys is going to be mixed as well with freezing lines between 4000 and 5500 feet over the next few days with several waves of moisture coming in.

advisory discussion

Snowmobiler/Snowbiker Travel Restrictions: Granite Mountain Area Closure is in effect Jan15-March 15, please respect Snowcats operating in this and nearby areas.  In addition there are other areas on the Payette National Forest that are CLOSED to snowmobile traffic including Jughandle Mt east of Jug Meadows,North of Boulder Mtn, East of Rapid Peak,  Lick Creek/Lake Fork Drainage (on the right side of the road as you are traveling up canyon), and the area north of Brundage Mt Ski area to junction "V" and along the east side of Brundage and Sergeants' Mts. with the exception of the Lookout Rd( junction "S").

 Please respect these closures and other users recreating in them.  Winter Travel Map(East side). You can download the map to the AVENZA app on your phone, and know your exact location while you are out riding.  It is your responsiblity to know where closures exist on the forest.

The Friends of the Payette Avalanche Center (FPAC) needs YOU! We are in desperate need of more user support and financial assistance. The avalanche forecast is not a guaranteed service, and is in jeopardy of dwindling down to only a couple of days a week in the near future. Please help if you can by clicking the DONATE tab above. If you value this life saving information, make a donation or help the FPAC in raising funds for the future

recent observations

Yesterday near Tamarack Resort wind was the major factor.  The morning started out wet and began to cool as a cold front pushed into the area around noon.  Snowlines climbed to 6500 feet through the morning with rain below until later in the afternoon. Upper elevations picked up between 2 an 5 inches of new snow and provided good skiing.  It wasn't enough to get rid of the crusts below but did a nice job softening up the skiing, snowmobiles are going to find plenty of firm snow again today with some areas of almost polished crust sticking out of the new snow.  Cornices, fresh wind slabs and wind drifts built rapidly through the day and were cracking easily under our skis.

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 22 deg. F.
Max. temperature in the last 24 hours: 30 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 13 mph
Maximum wind gust in the last 24 hours: 36 mph
New snowfall in the last 24 hours: inches
Total snow depth: 62 inches
weather

 

SHORT TERM...Today through Saturday...Next Pacific Storm system approaching the west coast today reaching the California coast this evening. An associated warm front will lift northward across the forecast area later today bringing another round of precipitation through Saturday morning. Snow level rise during the day from around 3500-4000 feet this morning to 4500 feet in the north and 5500 feet in the south by this evening. Valley will see between a quarter to half an inch of rain tonight. Mountains above 5500 feet will see 3 to 6 inches of snow. Mild temperatures expected through Saturday should continue snowmelt for the lower valleys. Rivers will begin to respond to the increased snowmelt and rainfall today with rises expected through the weekend.

LONG TERM...Saturday night through Thursday...A very active and wet pattern will continue through next week. There will likely be dry periods in between systems, although timing is difficult due to the progressive nature of the flow. The wettest period appears in the Monday-Monday night time frame as a very moist Southwest flow takes aim on the region. Snow levels will remain above the lowest valleys (including the Treasure Valley) through Tuesday, settling down to valley floors by Thursday as an upper trough moves into the region. Temperatures will be a few degrees above normal through Tuesday, trending downward to a few degrees below normal on Thursday.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Friday Friday Night Saturday
Weather: A 20 percent chance of snow showers before 11am. Mostly cloudy, with a high near 39. Light and variable wind. Rain and snow likely, mainly after 11pm. Cloudy, with a low around 31. Northeast wind around 5 mph becoming light and variable. Chance of precipitation is 60%. Little or no snow accumulation expected. Rain and snow, becoming all rain after 11am. High near 39. South wind 5 to 7 mph. Chance of precipitation is 90%. Little or no snow accumulation expected.
Temperatures: 39 deg. F. 31 deg. F. 39 deg. F.
Wind direction: Variable NW S
Wind speed: Light Around 5 mph 5-7
Expected snowfall: 0 in. Trace in. Trace in.
Granite Mountain at 7700 feet.
  Friday Friday Night Saturday
Weather: A 20 percent chance of snow showers before 11am. Mostly cloudy, with a high near 32. South wind around 8 mph. Snow likely, mainly after 11pm. Cloudy, with a low around 26. South wind 8 to 14 mph. Chance of precipitation is 60%. New snow accumulation of 1 to 2 inches possible Snow. High near 32. South wind 15 to 17 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible.
Temperatures: 32 deg. F. 26 deg. F. 32 deg. F.
Wind direction: S S S
Wind speed: Around 8 mph 8-14 15-17
Expected snowfall: 0 in. 1-2 in. 3-5 in.
Disclaimer

This avalanche advisory is provided through a partnership between the Payette National Forest and the Payette Avalanche Center. This advisory covers the West Central Mountains between Hard Butte on the north and Council Mountain on the south. This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires at midnight on the posted day unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.